1. Field of the Invention
The present invention relates to a vibration reduction device for reducing vibration such as camera shake.
2. Related Background Art
Japanese Patent Application Laid-Open Nos. 4-34513 and 4-34514 disclose vibration reduction devices each including a vibration reduction lens, a lens holding member for holding the vibration correction lens, a fixing member which is switched between a fixing position and a releasing position to fix and release the lens holding member, a tension coil spring for biasing the fixing member from the releasing position to the fixing position, a locking member which is engaged/disengaged with/from the fixing member to lock/release the fixing member at the releasing position, and a motor for driving the fixing member from the fixing position to the releasing position. In this vibration reduction device, the locked fixing member is released by the locking member to be quickly driven from the releasing position to the fixing position by the biasing force of the tension coil spring.
In the above conventional vibration reduction device, when the lens holding member is to be switched from a releasing state to a fixing state, the fixing member is driven by the biasing force of the tension coil spring. As a result, the lens holding member can be quickly fixed by the fixing member. In the conventional vibration reduction device, however, when the lens holding member is to be switched from the fixing state to the releasing state, the fixing member must be driven from the fixing position to the releasing position by the motor against the biasing force of the tension coil spring. For this reason, the conventional vibration reduction device requires a large quantity of electrical energy to switch the lens holding member from the fixing state to the releasing state. In addition, in the conventional vibration reduction device, the time required to switch the lens holding member to the releasing state is not negligible, and it is difficult to quickly switch the lens holding member to the releasing state to quickly start vibration reduction. Consequently, when the conventional vibration reduction device is mounted in a single-lens reflex still camera, the release time lag becomes long, resulting in a considerable deterioration in operability.
In the conventional vibration reduction device, in the process of switching the lens holding member from the releasing state to the fixing state, the user sometimes wants to resume vibration reduction by switching the lens holding member to the releasing state again. In such a case, according to the conventional vibration reduction device, the fixing member is driven first to the fixing position against the biasing force of the tension coil spring, and is then driven from the fixing position to the releasing position using the motor. It is, therefore, difficult for the conventional vibration reduction device to quickly resume vibration reduction.
Assume that in the vibration reduction device having the above structure, the lens holding member is in the releasing state (during vibration reduction). In this state, when the power switch is turned off, or the power supply battery is removed, the engagement between the fixing member and the locking member is canceled by driving the locking member until the capacitor incorporated in the camera body is discharged. For this reason, when the conventional vibration reduction device is mounted on the interchangeable lens of a single-lens reflex camera, and the interchangeable lens is removed from the camera body incorporating a power supply battery and a capacitor, the motor and the locking member cannot be driven without a power supply.